This invention relates to an integrated electronic security lock employing an electronic key which may be encoded by means of a control system coupled to the lock.
Various systems exist in the prior art for providing high security access to buildings. Generally, there is a trade-off in such systems between flexibility and security, whereby the most secure systems are relatively inflexibile. Thus, for example, in one system the finger prints of all authorised entrants are programmed into a computer, and an optical reader coupled to the computer is adapted to read the finger prints of people seeking access to the building, permitting entry only to those whose finger prints are stored in the computer memory. Such a system provides high security but is too inflexible to be serviceable for domestic premises, for example. Magnetic card keys also exist wherein a secret number is magnetically stored on the card, similar to the system employed in bank service cards. The user inserts the card into a suitable receptacle, and enters his personal code via a computer keyboard. Access will be granted only if the code thus entered corresponds to that stored magnetically on the card key. Such systems require the user to remember his personal code, and this effectively limits the total number of permutations of the code digits and, therefore, the security of the code. Thus, for example, if the code has only four digits, then the maximum number of permutations of the code is 10 000, assuming that each digit can have any value from 0 to 9. Moreover, such magnetic key cards may only be copied or encoded using special equipment which generally puts them out of the range of the domestic market.
Hotel security systems are also known which employ magnetic coded key cards, the security system comprising a computerized control unit by means of which the code corresponding to each hotel room may easily be changed.